1. Field of the Invention
The present invention relates to a construction of IC card.
2. Description of the Related Art
FIG. 6 shows a perspective view of a prior IC card, and FIG. 7 shows a sectional view along line a-a' of FIG. 6.
In FIGS. 6 and 7, the IC card 20 comprises an approximately U-shaped frame 1 made of resin or the like, metal panels 2a, 2b, a connector housing 3 made of plastic or the like, having sockets 6, into which various pins of an external system including power supply terminals, ground terminals, and signal conductors are inserted, and having socket leads 10, a reinforcing ground 4 consisting of a conductive metal member having at least one approximately semi-spherical protrusion 5 formed thereon and used for reducing the impedance of ground terminals, and a printed board 7 on which various devices are mounted.
The above connector housing 3 is fastened to frame 1 at its open end, and the reinforcing ground 4 is fastened to a face of connector housing 3 adjacent to the face into which external connector pins are inserted. The printed board 7 is fastened inside frame 1 to which the connector housing 3 is fastened, and each of socket leads 10 is connected to printed board 7. Further, frame 1 has a reinforcing portion 11 that bridges the opposite sides of frame 1 for reinforcement.
FIG. 8 is a perspective view of reinforcing ground 4. As seen from FIG. 8, reinforcing ground 4 has at least one connection lead 9, which is elongated approximately at the right angle to the plane portion 13 on which the protrusion 5 is formed in the direction opposite to the direction in which the protrusion 5 projects, and the end of each connection lead 9 is bent outward approximately in parallel to the plane portion 13. The end of each connection lead 9 is connected to the ground of printed board 7.
Metal panels 2a and 2b hold between themselves the frame 1 such that, as described above, connector housing 3 to which the reinforcing ground 4 is fastened is fastened to frame 1, printed board 7 is fastened inside frame 1, and each of connection leads 9 and socket leads 10 are connected to printed board 7. At this time, metal panel 2a is fastened to frame 1 in such a way as metal panel 2a does not contact reinforcing ground 4 so that the plane portion 13 having protrusions 5 of reinforcing ground 4 is exposed to the outside. Further, protrusions 5 of reinforcing ground 4 have sufficient height to stand above metal panel 2a and connector housing 3.
FIG. 9 shows the state in which the IC card 20 is inserted into a connector 19 of an external system equipment. In FIG. 9, connector 19 comprises connector pins 15, a connector body 16 made of resin or the like that fastens connector pins 15, a terminal 17 that connects the protrusions 5 of IC card 20 to itself by pressure contact. Terminal 17 is installed inside the slot, so that when connector pins 15 are inserted into corresponding sockets 6 of IC card 20, protrusions 5 contact terminal 17. The other end of terminal 17 is connected to a printed board 18 of the system equipment. In this way reinforcing ground 4 is used for reducing the impedance of the ground terminals in connector pins 15.
However, in an IC card having the above construction, metal panel 2a is fastened only to the U-shaped frame 1 and does not touch connector housing 3 or reinforcing ground 4, so that the corresponding part of metal panel 2a is kept loose without being supported by anything. Consequently, the part of metal panel 2a has little strength and easily broken if it is stressed. For example, if forces are applied to IC card 20 from the side of metal panel 2b, then the weak part of metal panel 2a warps outside. Therefore, there has been a problem that metal panel 2a is deformed in such a manner.